CA - repair versus start over

[BobRad]

I've been fighting with a CA finish since last night.

I started with BLO and thin CA then finished with One-Step Plastic Polish and at first glance it looked fine. A close look showed very minor scratches in the finish and I was sure it was in the CA, not the wood.

I just picked up some Novus plastic polish - never used it before so I thought I would try it. It took the CA down to a flat finish and I thought at first I had gone to the bare wood. However when I buffed back up to the the One-Step Plastic Polish and it was 80% excellent - no micro scratches - high glass - but 20% had no CA left.

I surface cleaned it and reapplied CA, WITHOUT sanding it all back to bare wood. Micromeshed it all again and this time its 99% good except for one small area, that is not high gloss. About to hit my head against the will, but I surface cleaned it again, and zapped some more CA on and walked out of the workshop

Even if it works this time, I wonder it the finish will be good, with all the reworking, adding different polishes - maybe I ended up leaving contaminants that will react later.

When do you give up on CA, and just sand it all away and start from scratch?

 

[tim self]

For me now would be a good time. But seriously, I only use thin for stabalizing and a quick seal coat. Then multiple coats of medium. About 6-8 then MM, Brasso and then plastic polish. Then buff at about 60-70 degree angle.

 

[mick]

If the dull spots are under the CA finish(this can sometimes be a result of the BLO)then reapplying CA without anding down to wood won't help. However if the dull spot is a result of sanding through the finish then a reapplication of CA will be ok. If you buffed a bare spot with a polish then that would have needed to be cleaned before applying CA. A lot depends on what kind of blank it is...I wouldn't bother too much with a piece of say maple, but on the other hand if it was a nice Amboyna blank then I'd go to more extremes. Hope this helps

 

[JD Combs Sr]

For me now would be a good time. But seriously, I only use thin for stabalizing and a quick seal coat. Then multiple coats of medium. About 6-8 then MM, Brasso and then plastic polish. Then buff at about 60-70 degree angle.

This is very much like how I do CA, a thin sealer coat then several medium coats. I may mm at 1500-1800 if I feel any roughness between coats, usually not. I have never tried Brasso, I go straight to the plastic polish and so far I have had excellent results. I don't have any data for how long it lasts but I have a 100 or so pens out that I used this process on. I guess I will eventually find out.

I just don't understand using BLO and CA together. I have read about it several times and thought about trying it but it just doesn't sound logical to me. I come from automotive engineering and we would never let oil of any kind get close to where we were finishing vehicles.

 

[BobRad]

That's how I felt, my experience as a self-taught part time furniture maker is that you don't mix finishes, but someone I trust who has been a professional cabinet maker all his life, told me it is ok.

I just don't understand using BLO and CA together. I have read about it several times and thought about trying it but it just doesn't sound logical to me. I come from automotive engineering and we would never let oil of any kind get close to where we were finishing vehicles.

 

[BobRad]

It is half of a Spalted Hackberry blank worth $1.25 - and if I wreck it, I still have the other half, but at this point I need the experience so that when its a $20 bit of wood, I know what to do

If the dull spots are under the CA finish(this can sometimes be a result of the BLO)then reapplying CA without anding down to wood won't help. However if the dull spot is a result of sanding through the finish then a reapplication of CA will be ok. If you buffed a bare spot with a polish then that would have needed to be cleaned before applying CA. A lot depends on what kind of blank it is...I wouldn't bother too much with a piece of say maple, but on the other hand if it was a nice Amboyna blank then I'd go to more extremes. Hope this helps

 

[mick]

It is half of a Spalted Hackberry blank worth $1.25 - and if I wreck it, I still have the other half, but at this point I need the experience so that when its a $20 bit of wood, I know what to do

Bob, that's the best thing, practice on your common inexpensive stuff, work out the kinks and then you'll be ready when it happens on your nicer, more expensive woods.
Sometimes it takes awhile to perfect a CA finish but once you do, you'll be amazed how swiftly and smoothly it can go.
Good luck!

 

[Craftdiggity]

Bob,

The easiest thing to do is start over. Just because it is the option with the fewest question marks. After all the time you have spent on it, trying to spot fix it at this point is not useful. Better to start from scratch and work on your overall technique. I'd rather be good at the initial application than fixing mistakes.

I'd eliminate the BLO first. Since you don't know if that is the problem, remove it from the equation and work with one material: CA. Get a few coats on, knock down the ridges, put some more on, and go from there.

 

[rsulli16]

yes you can


browsing thru the forum saw this. I just did it. I had sanded thru the CA on the high part of a barrell, ran out of CA. Left the blank in the lath, it was 2 days before i could get back to it. I was at Harbor Freight and brought a card of their super glue for 99 cents, didnt have time to go shopping, around her only one hobby shop carries a line of CA in thin, med and thick.
well today i used the cheap HF CA just went over it over and over again, it is real thin, but it worked. I even got some lint stuck on the lower blank and spot sanded that out and applied more of that CA. it worked for me!

 

[RussFairfield]

Don't pay any attention to what the furniture makers tell you. They don't use a CA finish, and the CA is harder, more brittle, less flexible. and has more problems mixing with other finishes, than anything they have ever used.

I have no idea what all of those other things you have used will do to a CA finish, and especially to one that hasn't been allowed to totally cure, and that can take a week. Always remember that CA will cure about 75% immediately, up to 85-90% in 24 hours, and that 100% can take several days. That remaining 10% can cause a lot of problems if incompatible finishes like oils and waxes are added to it.

My recommendation is to sand it down to the CA filled bare wood again, let it sit at least a week in an air conditioned room to make sure all moisture and everything else the wood has absorbed has a chance to evaporate. Then use a medium CA to finish the wood, and forget about mixing all of those other products with it.

If there is a roughness in the sanded surface after sitting for a week, then you will know that the wood is not dry and that moisture in the wood might be the source of your problems.